Charles pram-cis jenkins



644,382 Oct. 4 1 c. F. JENKINS. I

TWIN BLADE TRANSMITTER Filed March 2, 1925 sulator available, mica. for example.

Patented Get. 4, 1927.

rains CHARLES FRANCIS J ENK-INS, OF WASHINGTON, DISTRICT OF COLUMBIA.

TWIN BLADE TRANSMITTER.

Application filed March 2, 1925. Serial No. 12,594.

This invention relates to apparatus for the electrical transmission of pictures, sketches, drawings, maps, messages. etc, and has for its principal object the simplification of the processes employed in the translation of the subject (to be sent) into electrical energy to be transmitted by radio or by wire.

Heretofore these drawings, pictures. and such like subjects. have been prepared for transmission (1) by being photographed on transparent film, (2) made into a swelled gelatine print, (3) engraved in metal, (4)

drawn in insulating ink. and (5) various,

other schemes. all of which involve more or less complications and time-consuming preparations requiring technical dexterity.

The employment of this invention requires none of these. or any unusual process whatever. for the picture. sketch. message, or other subject matter is drawn or written on paper with the common lead pencil found n most everyones pocket.

This writing is then put on the cvlinder of the usual t pe of transmitting machine. and rotated under two-blade contacting device. the two blades being the terminals of the translating electrical circuit.

the graphite of the lead pencil is a conductor. it is pos ible to make a two-blade contact member which as it rubs over the pencil line will cause current to flow from one, blade to the other through the graphite ot the line.

Of course. it is desirable to have the blades iustas close together as po sible in order hat the writing need not be inordinate y large and still get the required refinement ot' detail.

The two-contact members should. there- 'tore. be separated by the thinnest good in- I These ont-act members being made of two very closely-associated metal fingers, thinned 'at the points. and having no greater separation than the width of the lines of the message, and rubbing over the-pencil-written message. translates the same into electrical current pulsations which are then put onto a wire or a radio wave, to be picked up at a distant point and put into readable form.

With this and other objects in view the invention consists in the novel details of assembly of the various devices employed, hereinafter disclosed and particularly pointed out in the claims.

In the drawings, Fig. 1 is a schematic cross-sectional view, and Fig. 2 an elevation of the instrument, in both of which A is a rotating cylinder. upon which a paper sheet B may be put, the sheet having a message, sketch, map, or the like thereon. Upon this cylinder-supported sheet the twin-blade metal contact member C bears, the two parts of which are insulated from each other by a thin sheet of mica, the whole being clamped together by the insulator blocks D and D (hard rubber, or the like).

Obviously if these two members. D and I). are the terminals of an electrical circuit any means of short-circuiting them would close the circuit, and this is exactly what the graphite pencil line does.

Therefore. the pencil. line of the writing as ing under the twin-blade contact member sends out electrical impulses which at a distant place can be reassembled into an intelligible message. the means for doing this being the subject of separate applications. i i

Of course. any other than a lead pencil line may be employed a. line oi any material which will short-circuit the two terminal blades. without departing from the spirit of m invention. and I. do not. theretore. wish to confine myself to the use of a lead pencil alone.

What I claim. is:-

I. In a device of the-class described. the combination oi two contact blades arran ed on opposite sides of a sheet 01 insulating material, a pair of insulating blocks embracing said blades and insulating material. means for clamping said blocks together, and a terminal mounted upon each block and connected respectively to one of said blades.

2. In a device of the class described, the combination of two contact blades arranged on opposite sides of a sheet of insulating material. each blade having formed at one end a pointed nib extending laterally in the same direction, and at the other end a terminal portion extending laterally in opposite directions to each other, a pair of insulating blocks embracing said blades and insulating materiaL' and means for clamping said blocks together.

' 3. In a device of the class described, the combination of two contact blades arranged on'opposite sides of a sheet of insulating material, each blade having formed at one end a pointed nib extending laterally in the same direction, and at the other end a terminal portion extending laterally in opposite directions to each other, a pair of insulating blocks embracing said blades and 'insulating material, means for clamping said blocks together, and a terminal mounted upon each block and connected respectively to the terminal portion of one of said blades. 10

In testimony whereof I have aflixed my signature.

CHARLES FRANCIS JENKINS. 

